Don't have a Motosen's fuel gauge (have their other stuff), but yes, they do work without modification with the Valkyrie sender... they are made for them.
The US distributor, Systron is based in Canada. What I did was order them online at their website,
http://www.motosens.com/usa/idea.htm I don't think you pay at that time. The next day I got a phone call from the distributor who reviewed the order over the phone and I gave them my CC#. Bout 2 weeks later, gauges arrived.
Systron Inc.
1274 3rd Avenue South
Lethbridge, Alberta
T1J 0J9 Canada